Improvement in feeding fuel to furnaces



A. L. SCHULTZ. Feeding Fuel to Furnaces.

'Pate'ntedlune 25,1878.

AUGUST L. SCHULTZ,

UNITED STATES PATENT OFFICE.

or MEIs'sEN, AssIeNon T0 BERNHARD RGBEB, or

DRESDEN, SAXONY.

IMPROVEMENT IN FEEDING FUEL TO FURNACES.

Specification forming part of Letters Patent No. 205,428, dated June 25,1878; application filed:

May 1, 1878.

To all whom it may concern:

Beit known that I, AUGUST LoUIs SCHULTZ, of Meissen, in the Kingdom ofSaxony, have invented certain Improvements in Feeding Fuel to Furnaces,of which the following is a description, reference being had to theaccompanying drawing, forming part of this specif cation.

This invention,'which has for its object .the

more perfect and economical combustion of the fuel on the gratesoffire-places and furnaces, relates to that description of the latter inwhich combustion is established and kept up by the feed of the fuel upto or beneath the burning mass, subject to a preliminary heating of thefresh fuel; and the invention consists in various novel construct-ionsand combinations of parts or devices, whereby these results, alsoperfect distribution and other advantages, are obtained.

In the accompanying drawing, Figure 1 rep resents a verticallongitudinal section of a steam -boiler furnace constructed inaccordance with my invention. Fig. 2 is a horizontal section of the sameon the line w w,- and Fig. 3 is a vertical section, on the line y y,through the supply-hopper and feeding-tube of the furnace.

A A represent the outside walls of a furnace of a steam-boiler, B, and OC the firebar portion of the grate. D is a fuel-supply-hopper, intowhich the coal or other fuel to be consumed on the grate is placed, andfrom which said fuel is conveyed, by a screwconveyer, E, to the fire-barportion of the grate, but not directly, as hereinafter described. Saidscrew-conveyer may be similar to other screw-conveyers for a likepurpose, and may be rotated, either by hand or by power, through theintervention of a wormwheel, F, and screw G, or by any other suitablemeans. Such screw-conveyer, however, is arranged to rotate within a feedtube or duct, H, of peculiar construction. Thus, said tube is of aclose-fittin g shape, conforming to the peripherical travel of thescrew-conveyer on that side, I), of the tube toward which the upperportion of said conveyer rotates, but is of tangential form to thegenerally circular contour of the tube on the opposite side, a, of

the latter, whereby the screw-conveyer is relieved from choking, andeffects a free and easy delivery or passage of the fuel along the ductor tube H.

The inner endof the feed tube or duct H is arranged to communicate witha passage, I, preferably made of increasing width toward the grate, andthe bottom of which is or may be formed of a hollow plate, J, having oneor more perforations in its upper surface, also along its front upperedge, and is provided below with an inlet-nozzle, d, for an artificialair-blast, when an artificial blast is needed, as in puddling, melting,and other furnaces for inctallurgic and other purposes requiring a hightemperature. lVhen a blast is used the air escaping from the hollowplate J is freely introduced to the fuel as it is fed or projected bythe screw-conveyer through and out of the passage I, said air beingdistributed not only up into the moving body of fuel, but also into itin direction of its motion toward the grate. The perforated hollow plateJ accordingly forms an air-blast distributer. The plate J may beprolonged or extended within the furnace any desired distance that maybe required. r

K is an inclined-plane portion of the grate, arranged at the front endof the latter, and sloping upwardly from the delivery end of the passageI toward the back of the grate. This inclined plane forms afeeding-trough for the fuel onto the firebars of the grate, and may bemade up of bars arranged close to one another, or otherwise have itsfeeding-surface of a close construction. Said inclined trough rises atits back end to the level of the the bars, or thereabout, and ispreferably formed with a series of steps, 6 e, at its sides, to secureits hold on the fuel and more perfect distribution of the fresh fuelunder the burning mass, and onto or over the whole fire-bar surface ofthe grate.

On commencing to fire up, the screw-coir veyer E is first operated tocover or nearly cover the whole grate with fuel 5 or the grate may bethus supplied through stoke-holes L L. The conveyer E is then set orcontinued in motion, and the fuel made to burn upon the whole surface ofthe grate, the green or fresh fuel, as it is fed forward by the actionof the conveyer and passes upwardly in its travel along th e in clinedtrough K, lifting and driving before it the burning upper mass or layersof fuel toward the rear end and sides of the grate. By such action thefuel which is consumed is regularly replaced by fresh fuel withoutreducin g the temperature of the furnace, the hot fuel being piled in afiat heap over the inclined trough, its stepped sides, and fire-bars ofthe grate, and as said heap is moved along, the

upper mass of burning fuel is distributed in various directions, whilethe fresh fuel forces its way from the center portion of the heap upwardandtoward the fire-bar surface of the grate.

The upper surface of the fire-bars is preferably in line or nearly inline with the longitudinal axis of the conveyer E.

The stoke-holes L L, which are furnished with doors, are mainly for thepurposeof removing the cinders or slag, and to pass the same onto orover either an opening andclosing trap at the rear of the grate, or ontothe rear portion 0 of the grate, which is hinged at its back and loweredor opened by means i of a nut, f, screw-rod g, cranks h i, and arockshaft, k, or other suitable means, to pass off 5 the slag whenrequired.

I claim 1. The combination, with the firebar portion of the grate, of anupwardlyinclining feeding-trough arranged to project within said portionof the grate and below the level of its fire-bars, substantially as andfor the purposes specified.

2. The upwardly-inclining feeding-trough, iconstructed with a series ofsteps on either side of it, in combination with the fire-bars of thegrate, arranged to meet on their upper surfaces the outer edges of thetrough, essentiall-y as described.

3. The combination, with the fire-bar portion 0' of the grate andupwardly-inclining I feeding-trough K, arranged to project within saidportion of the grate, of the hopper D,the .screw-conveyer E, the feedtube or duct H, ,constructed to closely hug said conveyer on its oneside I), and of atangential construction on its opposite side a, and thepassage T, sub gstantial-l-y as specified. I

at. The perforated air-blast distributer J, in combination with thepassage I, the upwardlyinclined feeding-trough K, and the fire-barportion of the grate, with which said trough T communicates, essentiallyas described.

This; specification signed by me this 29th 5 l -y Q D ce ber, 877-AUGUST o-Urs SCHULTZ.

W e ses:

BERNHARDT ROBER,

